Филип Дик: A Scanner Darkly

British Science Fiction Award (1978)

Bob Arctor is a dealer of the lethally addictive drug Substance D. Fred is the police agent assigned to tail and eventually bust him. To do so, Fred takes on the identity of a drug dealer named Bob Arctor. And since Substance D—which Arctor takes in massive doses—gradually splits the user’s brain into two distinct, combative entities, Fred doesn’t realize he is narcing on himself.